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/* vi: set sw=4 ts=4:
*
* xargs.c - Run command with arguments taken from stdin.
*
* Copyright 2011 Rob Landley <rob@landley.net>
*
* See http://opengroup.org/onlinepubs/9699919799/utilities/xargs.html
USE_XARGS(NEWTOY(xargs, "^I:E:L#ptxrn#<1s#0", TOYFLAG_USR|TOYFLAG_BIN))
config XARGS
bool "xargs"
default y
help
usage: xargs [-ptxr0] [-s NUM] [-n NUM] [-L NUM] [-E STR] COMMAND...
Run command line one or more times, appending arguments from stdin.
If command exits with 255, don't launch another even if arguments remain.
-s Size in bytes per command line
-n Max number of arguments per command
-0 Each argument is NULL terminated, no whitespace or quote processing
#-p Prompt for y/n from tty before running each command
#-t Trace, print command line to stderr
#-x Exit if can't fit everything in one command
#-r Don't run command with empty input
#-L Max number of lines of input per command
#-E stop at line matching string
*/
#include "toys.h"
DEFINE_GLOBALS(
long max_bytes;
long max_entries;
long L;
char *E;
char *I;
long entries, bytes;
char delim;
)
#define TT this.xargs
// According to man execv(5), the actual ARGS_MAX for linux is 128k (131072)
// meaning the theoretical maximum arguments (each one char) is 65536... but
// we can just use toybuf (1024 pointer on 32 bit, 512 on 64 bit).
#define ACTUAL_ARGS_MAX 131072
// If out==NULL count TT.bytes and TT.entries, stopping at max.
// Otherwise, fill out out[]
// Returning NULL means need more data.
// Returning 1 means hit data limits, but consumed all data
// Returning char * means hit data limits, start of data left over
static char *handle_entries(char *data, char **entry)
{
if (TT.delim) {
char *s = data;
// Chop up whitespace delimited string into args
while (*s) {
char *save;
while (isspace(*s)) {
if (entry) *s = 0;
s++;
}
if (TT.entries >= TT.max_entries && TT.max_entries)
return *s ? s : (char *)1;
if (!*s) break;
save = s;
for (;;) {
if (++TT.bytes >= TT.max_bytes && TT.max_bytes) return save;
if (!*s || isspace(*s)) break;
s++;
}
if (entry) entry[TT.entries] = save;
++TT.entries;
}
} else {
if (entry) entry[TT.entries] = data;
TT.bytes += strlen(data);
if (TT.bytes >= TT.max_bytes || ++TT.entries >= TT.max_entries)
return (char *)1;
}
return NULL;
}
void xargs_main(void)
{
struct double_list *dlist = NULL;
int entries, bytes, done = 0, status;
char *data = NULL;
if (!(toys.optflags&1)) TT.delim = '\n';
// If no optargs, call echo.
if (!toys.optc) {
free(toys.optargs);
*(toys.optargs=xzalloc(2*sizeof(char *)))="echo";
toys.optc=1;
}
for (entries = 0, bytes = -1; entries < toys.optc; entries++, bytes++)
bytes += strlen(toys.optargs[entries]);
// Loop through exec chunks.
while (data || !done) {
char **out;
TT.entries = 0;
TT.bytes = bytes;
// Loop reading input
for (;;) {
// Read line
if (!data) {
ssize_t l = 0;
l = getdelim(&data, (size_t *)&l, TT.delim, stdin);
if (l<0) {
data = 0;
done++;
break;
}
}
dlist_add(&dlist, data);
// Count data used
data = handle_entries(data, NULL);
if (!data) continue;
if (data == (char *)1) data = 0;
else data = xstrdup(data);
break;
}
// Accumulate cally thing
if (data && !TT.entries) error_exit("argument too long");
out = xzalloc((entries+TT.entries+1)*sizeof(char *));
if (dlist) {
struct double_list *dtemp;
// Fill out command line to exec
memcpy(out, toys.optargs, entries*sizeof(char *));
TT.entries = 0;
TT.bytes = bytes;
dlist->prev->next = 0;
for (dtemp = dlist; dtemp; dtemp = dtemp->next)
handle_entries(dtemp->data, out+entries);
}
pid_t pid=fork();
if (!pid) {
xclose(0);
open("/dev/null", O_RDONLY);
xexec(out);
}
waitpid(pid, &status, 0);
status = WEXITSTATUS(status);
// Abritrary number of execs, can't just leak memory each time...
while (dlist) {
struct double_list *dtemp = dlist->next;
free(dlist->data);
free(dlist);
dlist = dtemp;
}
free(out);
}
}
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